The invention relates to a method, a device and a system for displaying a vertical flight profile of an aircraft, and to an aircraft comprising such a device or such a system.
Aircraft, in particular passenger transport airplanes and military transport airplanes, comprise a flight management computer of FMS (flight management system) type. Generally, before a take-off of the aircraft, in a flight preparation phase or in a mission preparation phase of the aircraft, a pilot enters a flight plan into the FMS computer, this flight plan comprising a series of waypoints corresponding to the planned trajectory of the aircraft. A screen of the cockpit of the aircraft, associated with the FMS computer, enables the pilot to view the flight plan configured in the FMS computer and the pilot can, if necessary, modify this flight plan. Moreover, independently of this flight preparation phase, during the flight of the aircraft, the pilot has, in the cockpit, a navigation screen (navigation display), a first window of which displays a representation of the current flight plan of the aircraft in plan view in a horizontal plane and a second window, generally called VD (vertical display), displays a vertical flight profile in vertical plane along a trajectory of the aircraft corresponding to the current flight plan. The display of a window of VD type is notably illustrated by the documents FR 2,689,231 and FR 2,822,944. This second window comprises a y axis graduated by altitude, on which is displayed a symbol representing the aircraft at its current altitude, and an x axis graduated by distance from the current position of the aircraft. This window also comprises a plot representing the vertical trajectory of the aircraft along the flight plan, in front of the current position of the aircraft.
In the flight preparation phase or the mission preparation phase of the aircraft, it would be advantageous for the pilot to be able to view the vertical profile corresponding to the flight plan configured in the FMS computer, and to do so for the entire length of the flight plan, so as to be able to view the height margins relative to the terrain flown over or relative to altitude constraints. It would therefore be advantageous to have, during the flight preparation phase or the mission preparation phase of the aircraft, a display similar to a display of VD type. One problem which arises for the production of such a display relates to the vertical centering of the display window as a function of the part of the flight plan that the pilot wants to view. The document FR 2,895,793 describes a method for centering a window of VD type during the flight of a military transport aircraft. However, to determine the centering, this method uses information items relating to the current situation of the aircraft, notably the current position of the aircraft. It cannot therefore be transposed to the viewing of a part of the flight plan which would not be situated immediately in front of the aircraft, as in the case envisaged of a flight preparation phase or a mission preparation phase of an aircraft.